Annual ryegrass toxicity (staggers) is associated with the consumption of corynetoxin found in seed heads of infected plants. In NSW blowngrass is a common source of toxin. In other states, annual ryegrass commonly causes disease. This video clip was taken during an early outbreak in October 1990 in north western NSW.
Annual ryegrass toxicity (ARGT) is caused by the bacterium Rathayibacter toxicus.
This bacteria is carried by a nematode into the developing seed heads of some annual grasses, where it eventually produces a powerful tunicamycin-like poison called corynetoxin.
The most commonly affected plants include annual Wimmera ryegrass (Lolium rigidum) and blowngrass (Agrostis avenaceae).
The toxin may cause disease in cattle, sheep, goats, horses or pigs consuming infected seed heads.
Initial clinical signs include a reluctance to move and uncoordinated gait when driven. The death rate from ARGT can be very high.
Contributor Peter White and Peter Windsor
Clinical Findings Lolium rigidum poisoning